An ambitious space project is underway to help answer a fundamental question about our universe: Does life exist elsewhere in the solar system?

On April 14, the Jupiter Icy Moons Explorer (JUICE) successfully launched, with its sights set on the biggest planet in our orbit.

After 13 years in the making, the craft left from the European Space Agency spaceport in Kourou, French Guiana.

JUICE Mission

The mission is scheduled for arrival in the Jovian system (that is, the region of our outer planets) in mid-2031. But the craft will carry out a number of maneuvers en route to Jupiter and its moons.

Notably, it will be the first craft to perform a lunar-Earth gravity assist, taking advantage of the moon’s gravity to help slingshot it to its destination, saving a significant amount of fuel on its journey.

“JUICE will accomplish a number of solar system-exploration firsts,” says Athena Coustenis, an astrophysicist who specializes in planetology, and who has been involved in developing the JUICE mission.

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Jupiter Moons With Water

After the moon slingshot, JUICE will head for Ganymede, Europa and Callisto orbiting Jupiter.

These three Jovian moons are of highest interest to scientists because it is possible they carry extensive reservoirs of liquid water.

“It will be the first spacecraft ever to orbit a moon other than our own — Jupiter’s largest moon Ganymede,” Coustenis says. “After two Europa flybys and 21 Callisto flybys, the mission will culminate in a dedicated nine months orbital tour around Ganymede during which the spacecraft will perform detailed investigations of this moon and its environment.”

The spacecraft will also carry out extensive new studies of Jupiter’s atmosphere and magnetosphere and their relationship with the planet’s moons to help understand the system’s dynamics and how it evolved.

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Oceans Beneath the Surface of Icy Moons

Although they lie outside of the Goldilocks zone — which refers to an ideal distance from a star that would keep water in liquid form — Ganymede, Europa and Callisto are all expected to harbor liquid water oceans beneath their surface.

This is in part due to the continual stretching and compressing of the moons, in relation to their strong tidal interaction with Jupiter. It is thought the friction created from this interaction generates enough heat to keep water below the surface in liquid form.

In addition, radioactive decay from heavy elements in the moons’ cores may provide a source of heat.

“The mission will characterize the three moons both as planetary objects, highlighting their unique features, and as possible habitats [by] investigating their astrobiological potential,” Coustenis adds. 

The trip will also explore Jupiter’s complex environment, and study its wider system as an archetype for gas giants across the universe, including within other exoplanetary systems.

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Specialized Tools on the Jupiter Rocket

Once it reaches the system, JUICE will carry out a number of measurements with instruments that have been specifically engineered to deal with exposure to intense radiation.

JUICE’s payload consists of 10 state-of-the-art pieces of technology.

These include spectral imaging tools that can read ultraviolet and sub-millimeter wavelengths and a radar sounder for exploring the surface and subsurface of the moons.

The overall mission has been an international collaboration, with multiple people from different fields of expertise and countries coming together to work on a common goal.

Simultaneous Europa Missions

The undertaking also overlaps with NASA’s soon-to-be-launched Europa Clipper Mission, designed to place a radiation-tolerant reconnaissance spacecraft into Europa’s orbit.

Together, these efforts are set to provide groundbreaking new insights into the Jovian system, which should help answer various burning questions in the scientific community.

Finding large bodies of liquid water, organics and energy sources in any or all three of the Galilean icy moons could demonstrate that habitable conditions exist farther away from the sun than what traditional models of the ‘habitable zone’ in our solar system have suggested.

“This will help us search for signs of life in the right environments during future exploration,” Coustenis says.

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